Question

Classify the following change into physical and chemical changes:

Curdling of milk.

Answer 1

Physical change: It is a type of change in which there is no change in the substance's chemical properties and no new substance is formed.

• It is a type of reversible change.D
• Reversible change: It is a type of change that can be reversed easily and completely.
• For example Melting of ice, freezing of water, etc.

Chemical change: It is a type of change in which there is a change in the substance's chemical properties and a new substance is formed.

• It is a type of irreversible change.
• Irreversible change: It is a type of change that cannot be reversed.
• Heat will be released or absorbed in this type of reaction.
• For example: rusting of iron, formation of curd from milk, and curdling of milk.

Curdling of milk

• Curdling of milk in layman's language means the formation of panner from milk.
• It is a type of chemical change.
• When lime juice is added to milk the citric acid present in lime will make the milk acidic which results in the curdling of protein present in milk.
• Through this curdling panner will get separated leaving behind the water.
• This process is also a type of irreversible reaction and the composition of paneer is different than milk.

Therefore, the curdling of milk is a type of chemical change.